1. Technical Field
The present disclosure relates generally to endoscopic surgical instruments, and in particular to component arrangements and manufacturing processes suitable for use with instruments having relatively small end effectors.
2. Background of Related Art
Typically in a laparoscopic, an endoscopic, or other minimally invasive surgical procedure, a small incision or puncture is made in a patient's body. A cannula is then inserted into a body cavity through the incision, which provides a passageway for inserting various surgical devices such as scissors, dissectors, retractors, or similar instruments. To facilitate operability through the cannula, instruments adapted for laparoscopic surgery typically include a relatively narrow shaft supporting an end effector at its distal end and a handle at its proximal end. Arranging the shaft of such an instrument through the cannula allows a surgeon to manipulate the proximal handle from outside the body to cause the distal end effector to carry out a surgical procedure at a remote surgical site inside the body. This type of endoscopic procedure has proven beneficial over traditional open surgery due to reduced trauma, improved healing and other attendant advantages.
To fully realize the benefits of endoscopic surgery, instruments used for this purpose are typically designed to pass through a cannula providing a relatively small opening. For example, a cannula opening may have a diameter in the range of about five millimeters to about twelve millimeters. Even smaller openings may prove beneficial if instruments are designed without compromising the integrity or functionality of the instrument.
One type of endoscopic instrument that presents a particular challenge for designers is an electrosurgical forceps for sealing tissue. An electrosurgical forceps is a relatively complex instrument typically including several moving parts. For example, a pair of moveable jaw members may be provided for grasping tissue, and reciprocating blade may move to cut through the tissue at an appropriate time. Also contributing to the complexity is a stop member that controls the gap, or a minimum distance maintained between sealing surfaces of the jaw members. Maintaining an appropriate gap between the sealing surfaces is a necessary factor for forming an effective tissue seal. These and other manufacturing challenges become increasingly difficult to overcome when designing instruments to fit through smaller cannula openings. Conventional machining and assembly methods may lend difficulty to instrument manufacturing as the size of the components is reduced. Therefore, a jaw configuration that reduces the number or complexity of components may prove beneficial for small diameter instruments.